gdb/inferior.c

   1 /* Multi-process control for GDB, the GNU debugger.
   2
   3    Copyright (C) 2008-2017 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "exec.h"
  22 #include "inferior.h"
  23 #include "target.h"
  24 #include "command.h"
  25 #include "completer.h"
  26 #include "gdbcmd.h"
  27 #include "gdbthread.h"
  28 #include "ui-out.h"
  29 #include "observer.h"
  30 #include "gdbcore.h"
  31 #include "symfile.h"
  32 #include "environ.h"
  33 #include "cli/cli-utils.h"
  34 #include "continuations.h"
  35 #include "arch-utils.h"
  36 #include "target-descriptions.h"
  37 #include "readline/tilde.h"
  38 #include "progspace-and-thread.h"
  39
  40 void _initialize_inferiors (void);
  41
  42 /* Keep a registry of per-inferior data-pointers required by other GDB
  43    modules.  */
  44
  45 DEFINE_REGISTRY (inferior, REGISTRY_ACCESS_FIELD)
  46
  47 struct inferior *inferior_list = NULL;
  48 static int highest_inferior_num;
  49
  50 /* Print notices on inferior events (attach, detach, etc.), set with
  51    `set print inferior-events'.  */
  52 static int print_inferior_events = 0;
  53
  54 /* The Current Inferior.  This is a strong reference.  I.e., whenever
  55    an inferior is the current inferior, its refcount is
  56    incremented.  */
  57 static struct inferior *current_inferior_ = NULL;
  58
  59 struct inferior*
  60 current_inferior (void)
  61 {
  62   return current_inferior_;
  63 }
  64
  65 void
  66 set_current_inferior (struct inferior *inf)
  67 {
  68   /* There's always an inferior.  */
  69   gdb_assert (inf != NULL);
  70
  71   inf->incref ();
  72   current_inferior_->decref ();
  73   current_inferior_ = inf;
  74 }
  75
  76 inferior::~inferior ()
  77 {
  78   inferior *inf = this;
  79
  80   discard_all_inferior_continuations (inf);
  81   inferior_free_data (inf);
  82   xfree (inf->args);
  83   xfree (inf->terminal);
  84   free_environ (inf->environment);
  85   target_desc_info_free (inf->tdesc_info);
  86   xfree (inf->priv);
  87 }
  88
  89 inferior::inferior (int pid_)
  90   : num (++highest_inferior_num),
  91     pid (pid_),
  92     environment (make_environ ()),
  93     registry_data ()
  94 {
  95   init_environ (this->environment);
  96   inferior_alloc_data (this);
  97 }
  98
  99 struct inferior *
 100 add_inferior_silent (int pid)
 101 {
 102   inferior *inf = new inferior (pid);
 103
 104   if (inferior_list == NULL)
 105     inferior_list = inf;
 106   else
 107     {
 108       inferior *last;
 109
 110       for (last = inferior_list; last->next != NULL; last = last->next)
 111         ;
 112       last->next = inf;
 113     }
 114
 115   observer_notify_inferior_added (inf);
 116
 117   if (pid != 0)
 118     inferior_appeared (inf, pid);
 119
 120   return inf;
 121 }
 122
 123 struct inferior *
 124 add_inferior (int pid)
 125 {
 126   struct inferior *inf = add_inferior_silent (pid);
 127
 128   if (print_inferior_events)
 129     printf_unfiltered (_("[New inferior %d]\n"), pid);
 130
 131   return inf;
 132 }
 133
 134 struct delete_thread_of_inferior_arg
 135 {
 136   int pid;
 137   int silent;
 138 };
 139
 140 static int
 141 delete_thread_of_inferior (struct thread_info *tp, void *data)
 142 {
 143   struct delete_thread_of_inferior_arg *arg
 144     = (struct delete_thread_of_inferior_arg *) data;
 145
 146   if (ptid_get_pid (tp->ptid) == arg->pid)
 147     {
 148       if (arg->silent)
 149         delete_thread_silent (tp->ptid);
 150       else
 151         delete_thread (tp->ptid);
 152     }
 153
 154   return 0;
 155 }
 156
 157 void
 158 delete_inferior (struct inferior *todel)
 159 {
 160   struct inferior *inf, *infprev;
 161   struct delete_thread_of_inferior_arg arg;
 162
 163   infprev = NULL;
 164
 165   for (inf = inferior_list; inf; infprev = inf, inf = inf->next)
 166     if (inf == todel)
 167       break;
 168
 169   if (!inf)
 170     return;
 171
 172   arg.pid = inf->pid;
 173   arg.silent = 1;
 174
 175   iterate_over_threads (delete_thread_of_inferior, &arg);
 176
 177   if (infprev)
 178     infprev->next = inf->next;
 179   else
 180     inferior_list = inf->next;
 181
 182   observer_notify_inferior_removed (inf);
 183
 184   /* If this program space is rendered useless, remove it. */
 185   if (program_space_empty_p (inf->pspace))
 186     delete_program_space (inf->pspace);
 187
 188   delete inf;
 189 }
 190
 191 /* If SILENT then be quiet -- don't announce a inferior exit, or the
 192    exit of its threads.  */
 193
 194 static void
 195 exit_inferior_1 (struct inferior *inftoex, int silent)
 196 {
 197   struct inferior *inf;
 198   struct delete_thread_of_inferior_arg arg;
 199
 200   for (inf = inferior_list; inf; inf = inf->next)
 201     if (inf == inftoex)
 202       break;
 203
 204   if (!inf)
 205     return;
 206
 207   arg.pid = inf->pid;
 208   arg.silent = silent;
 209
 210   iterate_over_threads (delete_thread_of_inferior, &arg);
 211
 212   observer_notify_inferior_exit (inf);
 213
 214   inf->pid = 0;
 215   inf->fake_pid_p = 0;
 216   xfree (inf->priv);
 217   inf->priv = NULL;
 218
 219   if (inf->vfork_parent != NULL)
 220     {
 221       inf->vfork_parent->vfork_child = NULL;
 222       inf->vfork_parent = NULL;
 223     }
 224   if (inf->vfork_child != NULL)
 225     {
 226       inf->vfork_child->vfork_parent = NULL;
 227       inf->vfork_child = NULL;
 228     }
 229
 230   inf->pending_detach = 0;
 231 }
 232
 233 void
 234 exit_inferior (int pid)
 235 {
 236   struct inferior *inf = find_inferior_pid (pid);
 237
 238   exit_inferior_1 (inf, 0);
 239
 240   if (print_inferior_events)
 241     printf_unfiltered (_("[Inferior %d exited]\n"), pid);
 242 }
 243
 244 void
 245 exit_inferior_silent (int pid)
 246 {
 247   struct inferior *inf = find_inferior_pid (pid);
 248
 249   exit_inferior_1 (inf, 1);
 250 }
 251
 252 void
 253 exit_inferior_num_silent (int num)
 254 {
 255   struct inferior *inf = find_inferior_id (num);
 256
 257   exit_inferior_1 (inf, 1);
 258 }
 259
 260 void
 261 detach_inferior (int pid)
 262 {
 263   struct inferior *inf = find_inferior_pid (pid);
 264
 265   exit_inferior_1 (inf, 0);
 266
 267   if (print_inferior_events)
 268     printf_unfiltered (_("[Inferior %d detached]\n"), pid);
 269 }
 270
 271 void
 272 inferior_appeared (struct inferior *inf, int pid)
 273 {
 274   inf->pid = pid;
 275   inf->has_exit_code = 0;
 276   inf->exit_code = 0;
 277
 278   observer_notify_inferior_appeared (inf);
 279 }
 280
 281 void
 282 discard_all_inferiors (void)
 283 {
 284   struct inferior *inf;
 285
 286   for (inf = inferior_list; inf; inf = inf->next)
 287     {
 288       if (inf->pid != 0)
 289         exit_inferior_silent (inf->pid);
 290     }
 291 }
 292
 293 struct inferior *
 294 find_inferior_id (int num)
 295 {
 296   struct inferior *inf;
 297
 298   for (inf = inferior_list; inf; inf = inf->next)
 299     if (inf->num == num)
 300       return inf;
 301
 302   return NULL;
 303 }
 304
 305 struct inferior *
 306 find_inferior_pid (int pid)
 307 {
 308   struct inferior *inf;
 309
 310   /* Looking for inferior pid == 0 is always wrong, and indicative of
 311      a bug somewhere else.  There may be more than one with pid == 0,
 312      for instance.  */
 313   gdb_assert (pid != 0);
 314
 315   for (inf = inferior_list; inf; inf = inf->next)
 316     if (inf->pid == pid)
 317       return inf;
 318
 319   return NULL;
 320 }
 321
 322 /* See inferior.h */
 323
 324 struct inferior *
 325 find_inferior_ptid (ptid_t ptid)
 326 {
 327   return find_inferior_pid (ptid_get_pid (ptid));
 328 }
 329
 330 /* See inferior.h.  */
 331
 332 struct inferior *
 333 find_inferior_for_program_space (struct program_space *pspace)
 334 {
 335   struct inferior *inf = current_inferior ();
 336
 337   if (inf->pspace == pspace)
 338     return inf;
 339
 340   for (inf = inferior_list; inf != NULL; inf = inf->next)
 341     {
 342       if (inf->pspace == pspace)
 343         return inf;
 344     }
 345
 346   return NULL;
 347 }
 348
 349 struct inferior *
 350 iterate_over_inferiors (int (*callback) (struct inferior *, void *),
 351                         void *data)
 352 {
 353   struct inferior *inf, *infnext;
 354
 355   for (inf = inferior_list; inf; inf = infnext)
 356     {
 357       infnext = inf->next;
 358       if ((*callback) (inf, data))
 359         return inf;
 360     }
 361
 362   return NULL;
 363 }
 364
 365 int
 366 valid_gdb_inferior_id (int num)
 367 {
 368   struct inferior *inf;
 369
 370   for (inf = inferior_list; inf; inf = inf->next)
 371     if (inf->num == num)
 372       return 1;
 373
 374   return 0;
 375 }
 376
 377 int
 378 pid_to_gdb_inferior_id (int pid)
 379 {
 380   struct inferior *inf;
 381
 382   for (inf = inferior_list; inf; inf = inf->next)
 383     if (inf->pid == pid)
 384       return inf->num;
 385
 386   return 0;
 387 }
 388
 389 int
 390 gdb_inferior_id_to_pid (int num)
 391 {
 392   struct inferior *inferior = find_inferior_id (num);
 393   if (inferior)
 394     return inferior->pid;
 395   else
 396     return -1;
 397 }
 398
 399 int
 400 in_inferior_list (int pid)
 401 {
 402   struct inferior *inf;
 403
 404   for (inf = inferior_list; inf; inf = inf->next)
 405     if (inf->pid == pid)
 406       return 1;
 407
 408   return 0;
 409 }
 410
 411 int
 412 have_inferiors (void)
 413 {
 414   struct inferior *inf;
 415
 416   for (inf = inferior_list; inf; inf = inf->next)
 417     if (inf->pid != 0)
 418       return 1;
 419
 420   return 0;
 421 }
 422
 423 /* Return the number of live inferiors.  We account for the case
 424    where an inferior might have a non-zero pid but no threads, as
 425    in the middle of a 'mourn' operation.  */
 426
 427 int
 428 number_of_live_inferiors (void)
 429 {
 430   struct inferior *inf;
 431   int num_inf = 0;
 432
 433   for (inf = inferior_list; inf; inf = inf->next)
 434     if (inf->pid != 0)
 435       {
 436         struct thread_info *tp;
 437
 438         ALL_NON_EXITED_THREADS (tp)
 439          if (tp && ptid_get_pid (tp->ptid) == inf->pid)
 440            if (target_has_execution_1 (tp->ptid))
 441              {
 442                /* Found a live thread in this inferior, go to the next
 443                   inferior.  */
 444                ++num_inf;
 445                break;
 446              }
 447       }
 448
 449   return num_inf;
 450 }
 451
 452 /* Return true if there is at least one live inferior.  */
 453
 454 int
 455 have_live_inferiors (void)
 456 {
 457   return number_of_live_inferiors () > 0;
 458 }
 459
 460 /* Prune away any unused inferiors, and then prune away no longer used
 461    program spaces.  */
 462
 463 void
 464 prune_inferiors (void)
 465 {
 466   struct inferior *ss, **ss_link;
 467
 468   ss = inferior_list;
 469   ss_link = &inferior_list;
 470   while (ss)
 471     {
 472       if (!ss->deletable ()
 473           || !ss->removable
 474           || ss->pid != 0)
 475         {
 476           ss_link = &ss->next;
 477           ss = *ss_link;
 478           continue;
 479         }
 480
 481       *ss_link = ss->next;
 482       delete_inferior (ss);
 483       ss = *ss_link;
 484     }
 485 }
 486
 487 /* Simply returns the count of inferiors.  */
 488
 489 int
 490 number_of_inferiors (void)
 491 {
 492   struct inferior *inf;
 493   int count = 0;
 494
 495   for (inf = inferior_list; inf != NULL; inf = inf->next)
 496     count++;
 497
 498   return count;
 499 }
 500
 501 /* Converts an inferior process id to a string.  Like
 502    target_pid_to_str, but special cases the null process.  */
 503
 504 static const char *
 505 inferior_pid_to_str (int pid)
 506 {
 507   if (pid != 0)
 508     return target_pid_to_str (pid_to_ptid (pid));
 509   else
 510     return _("<null>");
 511 }
 512
 513 /* See inferior.h.  */
 514
 515 void
 516 print_selected_inferior (struct ui_out *uiout)
 517 {
 518   struct inferior *inf = current_inferior ();
 519   const char *filename = inf->pspace->pspace_exec_filename;
 520
 521   if (filename == NULL)
 522     filename = _("<noexec>");
 523
 524   uiout->message (_("[Switching to inferior %d [%s] (%s)]\n"),
 525                   inf->num, inferior_pid_to_str (inf->pid), filename);
 526 }
 527
 528 /* Prints the list of inferiors and their details on UIOUT.  This is a
 529    version of 'info_inferior_command' suitable for use from MI.
 530
 531    If REQUESTED_INFERIORS is not NULL, it's a list of GDB ids of the
 532    inferiors that should be printed.  Otherwise, all inferiors are
 533    printed.  */
 534
 535 static void
 536 print_inferior (struct ui_out *uiout, char *requested_inferiors)
 537 {
 538   struct inferior *inf;
 539   struct cleanup *old_chain;
 540   int inf_count = 0;
 541
 542   /* Compute number of inferiors we will print.  */
 543   for (inf = inferior_list; inf; inf = inf->next)
 544     {
 545       if (!number_is_in_list (requested_inferiors, inf->num))
 546         continue;
 547
 548       ++inf_count;
 549     }
 550
 551   if (inf_count == 0)
 552     {
 553       uiout->message ("No inferiors.\n");
 554       return;
 555     }
 556
 557   old_chain = make_cleanup_ui_out_table_begin_end (uiout, 4, inf_count,
 558                                                    "inferiors");
 559   uiout->table_header (1, ui_left, "current", "");
 560   uiout->table_header (4, ui_left, "number", "Num");
 561   uiout->table_header (17, ui_left, "target-id", "Description");
 562   uiout->table_header (17, ui_left, "exec", "Executable");
 563
 564   uiout->table_body ();
 565   for (inf = inferior_list; inf; inf = inf->next)
 566     {
 567       if (!number_is_in_list (requested_inferiors, inf->num))
 568         continue;
 569
 570       ui_out_emit_tuple tuple_emitter (uiout, NULL);
 571
 572       if (inf == current_inferior ())
 573         uiout->field_string ("current", "*");
 574       else
 575         uiout->field_skip ("current");
 576
 577       uiout->field_int ("number", inf->num);
 578
 579       uiout->field_string ("target-id", inferior_pid_to_str (inf->pid));
 580
 581       if (inf->pspace->pspace_exec_filename != NULL)
 582         uiout->field_string ("exec", inf->pspace->pspace_exec_filename);
 583       else
 584         uiout->field_skip ("exec");
 585
 586       /* Print extra info that isn't really fit to always present in
 587          tabular form.  Currently we print the vfork parent/child
 588          relationships, if any.  */
 589       if (inf->vfork_parent)
 590         {
 591           uiout->text (_("\n\tis vfork child of inferior "));
 592           uiout->field_int ("vfork-parent", inf->vfork_parent->num);
 593         }
 594       if (inf->vfork_child)
 595         {
 596           uiout->text (_("\n\tis vfork parent of inferior "));
 597           uiout->field_int ("vfork-child", inf->vfork_child->num);
 598         }
 599
 600       uiout->text ("\n");
 601     }
 602
 603   do_cleanups (old_chain);
 604 }
 605
 606 static void
 607 detach_inferior_command (char *args, int from_tty)
 608 {
 609   struct thread_info *tp;
 610
 611   if (!args || !*args)
 612     error (_("Requires argument (inferior id(s) to detach)"));
 613
 614   number_or_range_parser parser (args);
 615   while (!parser.finished ())
 616     {
 617       int num = parser.get_number ();
 618
 619       if (!valid_gdb_inferior_id (num))
 620         {
 621           warning (_("Inferior ID %d not known."), num);
 622           continue;
 623         }
 624
 625       int pid = gdb_inferior_id_to_pid (num);
 626       if (pid == 0)
 627         {
 628           warning (_("Inferior ID %d is not running."), num);
 629           continue;
 630         }
 631
 632       tp = any_thread_of_process (pid);
 633       if (!tp)
 634         {
 635           warning (_("Inferior ID %d has no threads."), num);
 636           continue;
 637         }
 638
 639       switch_to_thread (tp->ptid);
 640
 641       detach_command (NULL, from_tty);
 642     }
 643 }
 644
 645 static void
 646 kill_inferior_command (char *args, int from_tty)
 647 {
 648   struct thread_info *tp;
 649
 650   if (!args || !*args)
 651     error (_("Requires argument (inferior id(s) to kill)"));
 652
 653   number_or_range_parser parser (args);
 654   while (!parser.finished ())
 655     {
 656       int num = parser.get_number ();
 657
 658       if (!valid_gdb_inferior_id (num))
 659         {
 660           warning (_("Inferior ID %d not known."), num);
 661           continue;
 662         }
 663
 664       int pid = gdb_inferior_id_to_pid (num);
 665       if (pid == 0)
 666         {
 667           warning (_("Inferior ID %d is not running."), num);
 668           continue;
 669         }
 670
 671       tp = any_thread_of_process (pid);
 672       if (!tp)
 673         {
 674           warning (_("Inferior ID %d has no threads."), num);
 675           continue;
 676         }
 677
 678       switch_to_thread (tp->ptid);
 679
 680       target_kill ();
 681     }
 682
 683   bfd_cache_close_all ();
 684 }
 685
 686 static void
 687 inferior_command (char *args, int from_tty)
 688 {
 689   struct inferior *inf;
 690   int num;
 691
 692   num = parse_and_eval_long (args);
 693
 694   inf = find_inferior_id (num);
 695   if (inf == NULL)
 696     error (_("Inferior ID %d not known."), num);
 697
 698   if (inf->pid != 0)
 699     {
 700       if (inf->pid != ptid_get_pid (inferior_ptid))
 701         {
 702           struct thread_info *tp;
 703
 704           tp = any_thread_of_process (inf->pid);
 705           if (!tp)
 706             error (_("Inferior has no threads."));
 707
 708           switch_to_thread (tp->ptid);
 709         }
 710
 711       observer_notify_user_selected_context_changed
 712         (USER_SELECTED_INFERIOR
 713          | USER_SELECTED_THREAD
 714          | USER_SELECTED_FRAME);
 715     }
 716   else
 717     {
 718       set_current_inferior (inf);
 719       switch_to_thread (null_ptid);
 720       set_current_program_space (inf->pspace);
 721
 722       observer_notify_user_selected_context_changed (USER_SELECTED_INFERIOR);
 723     }
 724 }
 725
 726 /* Print information about currently known inferiors.  */
 727
 728 static void
 729 info_inferiors_command (char *args, int from_tty)
 730 {
 731   print_inferior (current_uiout, args);
 732 }
 733
 734 /* remove-inferior ID */
 735
 736 static void
 737 remove_inferior_command (char *args, int from_tty)
 738 {
 739   if (args == NULL || *args == '\0')
 740     error (_("Requires an argument (inferior id(s) to remove)"));
 741
 742   number_or_range_parser parser (args);
 743   while (!parser.finished ())
 744     {
 745       int num = parser.get_number ();
 746       struct inferior *inf = find_inferior_id (num);
 747
 748       if (inf == NULL)
 749         {
 750           warning (_("Inferior ID %d not known."), num);
 751           continue;
 752         }
 753
 754       if (!inf->deletable ())
 755         {
 756           warning (_("Can not remove current inferior %d."), num);
 757           continue;
 758         }
 759
 760       if (inf->pid != 0)
 761         {
 762           warning (_("Can not remove active inferior %d."), num);
 763           continue;
 764         }
 765
 766       delete_inferior (inf);
 767     }
 768 }
 769
 770 struct inferior *
 771 add_inferior_with_spaces (void)
 772 {
 773   struct address_space *aspace;
 774   struct program_space *pspace;
 775   struct inferior *inf;
 776   struct gdbarch_info info;
 777
 778   /* If all inferiors share an address space on this system, this
 779      doesn't really return a new address space; otherwise, it
 780      really does.  */
 781   aspace = maybe_new_address_space ();
 782   pspace = add_program_space (aspace);
 783   inf = add_inferior (0);
 784   inf->pspace = pspace;
 785   inf->aspace = pspace->aspace;
 786
 787   /* Setup the inferior's initial arch, based on information obtained
 788      from the global "set ..." options.  */
 789   gdbarch_info_init (&info);
 790   inf->gdbarch = gdbarch_find_by_info (info);
 791   /* The "set ..." options reject invalid settings, so we should
 792      always have a valid arch by now.  */
 793   gdb_assert (inf->gdbarch != NULL);
 794
 795   return inf;
 796 }
 797
 798 /* add-inferior [-copies N] [-exec FILENAME]  */
 799
 800 static void
 801 add_inferior_command (char *args, int from_tty)
 802 {
 803   int i, copies = 1;
 804   char *exec = NULL;
 805   char **argv;
 806   symfile_add_flags add_flags = 0;
 807   struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
 808
 809   if (from_tty)
 810     add_flags |= SYMFILE_VERBOSE;
 811
 812   if (args)
 813     {
 814       argv = gdb_buildargv (args);
 815       make_cleanup_freeargv (argv);
 816
 817       for (; *argv != NULL; argv++)
 818         {
 819           if (**argv == '-')
 820             {
 821               if (strcmp (*argv, "-copies") == 0)
 822                 {
 823                   ++argv;
 824                   if (!*argv)
 825                     error (_("No argument to -copies"));
 826                   copies = parse_and_eval_long (*argv);
 827                 }
 828               else if (strcmp (*argv, "-exec") == 0)
 829                 {
 830                   ++argv;
 831                   if (!*argv)
 832                     error (_("No argument to -exec"));
 833                   exec = tilde_expand (*argv);
 834                   make_cleanup (xfree, exec);
 835                 }
 836             }
 837           else
 838             error (_("Invalid argument"));
 839         }
 840     }
 841
 842   scoped_restore_current_pspace_and_thread restore_pspace_thread;
 843
 844   for (i = 0; i < copies; ++i)
 845     {
 846       struct inferior *inf = add_inferior_with_spaces ();
 847
 848       printf_filtered (_("Added inferior %d\n"), inf->num);
 849
 850       if (exec != NULL)
 851         {
 852           /* Switch over temporarily, while reading executable and
 853              symbols.q.  */
 854           set_current_program_space (inf->pspace);
 855           set_current_inferior (inf);
 856           switch_to_thread (null_ptid);
 857
 858           exec_file_attach (exec, from_tty);
 859           symbol_file_add_main (exec, add_flags);
 860         }
 861     }
 862
 863   do_cleanups (old_chain);
 864 }
 865
 866 /* clone-inferior [-copies N] [ID] */
 867
 868 static void
 869 clone_inferior_command (char *args, int from_tty)
 870 {
 871   int i, copies = 1;
 872   char **argv;
 873   struct inferior *orginf = NULL;
 874   struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
 875
 876   if (args)
 877     {
 878       argv = gdb_buildargv (args);
 879       make_cleanup_freeargv (argv);
 880
 881       for (; *argv != NULL; argv++)
 882         {
 883           if (**argv == '-')
 884             {
 885               if (strcmp (*argv, "-copies") == 0)
 886                 {
 887                   ++argv;
 888                   if (!*argv)
 889                     error (_("No argument to -copies"));
 890                   copies = parse_and_eval_long (*argv);
 891
 892                   if (copies < 0)
 893                     error (_("Invalid copies number"));
 894                 }
 895             }
 896           else
 897             {
 898               if (orginf == NULL)
 899                 {
 900                   int num;
 901
 902                   /* The first non-option (-) argument specified the
 903                      program space ID.  */
 904                   num = parse_and_eval_long (*argv);
 905                   orginf = find_inferior_id (num);
 906
 907                   if (orginf == NULL)
 908                     error (_("Inferior ID %d not known."), num);
 909                   continue;
 910                 }
 911               else
 912                 error (_("Invalid argument"));
 913             }
 914         }
 915     }
 916
 917   /* If no inferior id was specified, then the user wants to clone the
 918      current inferior.  */
 919   if (orginf == NULL)
 920     orginf = current_inferior ();
 921
 922   scoped_restore_current_pspace_and_thread restore_pspace_thread;
 923
 924   for (i = 0; i < copies; ++i)
 925     {
 926       struct address_space *aspace;
 927       struct program_space *pspace;
 928       struct inferior *inf;
 929
 930       /* If all inferiors share an address space on this system, this
 931          doesn't really return a new address space; otherwise, it
 932          really does.  */
 933       aspace = maybe_new_address_space ();
 934       pspace = add_program_space (aspace);
 935       inf = add_inferior (0);
 936       inf->pspace = pspace;
 937       inf->aspace = pspace->aspace;
 938       inf->gdbarch = orginf->gdbarch;
 939
 940       /* If the original inferior had a user specified target
 941          description, make the clone use it too.  */
 942       if (target_desc_info_from_user_p (inf->tdesc_info))
 943         copy_inferior_target_desc_info (inf, orginf);
 944
 945       printf_filtered (_("Added inferior %d.\n"), inf->num);
 946
 947       set_current_inferior (inf);
 948       switch_to_thread (null_ptid);
 949       clone_program_space (pspace, orginf->pspace);
 950     }
 951
 952   do_cleanups (old_chain);
 953 }
 954
 955 /* Print notices when new inferiors are created and die.  */
 956 static void
 957 show_print_inferior_events (struct ui_file *file, int from_tty,
 958                            struct cmd_list_element *c, const char *value)
 959 {
 960   fprintf_filtered (file, _("Printing of inferior events is %s.\n"), value);
 961 }
 962
 963 /* Return a new value for the selected inferior's id.  */
 964
 965 static struct value *
 966 inferior_id_make_value (struct gdbarch *gdbarch, struct internalvar *var,
 967                         void *ignore)
 968 {
 969   struct inferior *inf = current_inferior ();
 970
 971   return value_from_longest (builtin_type (gdbarch)->builtin_int, inf->num);
 972 }
 973
 974 /* Implementation of `$_inferior' variable.  */
 975
 976 static const struct internalvar_funcs inferior_funcs =
 977 {
 978   inferior_id_make_value,
 979   NULL,
 980   NULL
 981 };
 982
 983 \f
 984
 985 void
 986 initialize_inferiors (void)
 987 {
 988   struct cmd_list_element *c = NULL;
 989
 990   /* There's always one inferior.  Note that this function isn't an
 991      automatic _initialize_foo function, since other _initialize_foo
 992      routines may need to install their per-inferior data keys.  We
 993      can only allocate an inferior when all those modules have done
 994      that.  Do this after initialize_progspace, due to the
 995      current_program_space reference.  */
 996   current_inferior_ = add_inferior (0);
 997   current_inferior_->incref ();
 998   current_inferior_->pspace = current_program_space;
 999   current_inferior_->aspace = current_program_space->aspace;
1000   /* The architecture will be initialized shortly, by
1001      initialize_current_architecture.  */
1002
1003   add_info ("inferiors", info_inferiors_command,
1004             _("IDs of specified inferiors (all inferiors if no argument)."));
1005
1006   c = add_com ("add-inferior", no_class, add_inferior_command, _("\
1007 Add a new inferior.\n\
1008 Usage: add-inferior [-copies <N>] [-exec <FILENAME>]\n\
1009 N is the optional number of inferiors to add, default is 1.\n\
1010 FILENAME is the file name of the executable to use\n\
1011 as main program."));
1012   set_cmd_completer (c, filename_completer);
1013
1014   add_com ("remove-inferiors", no_class, remove_inferior_command, _("\
1015 Remove inferior ID (or list of IDs).\n\
1016 Usage: remove-inferiors ID..."));
1017
1018   add_com ("clone-inferior", no_class, clone_inferior_command, _("\
1019 Clone inferior ID.\n\
1020 Usage: clone-inferior [-copies <N>] [ID]\n\
1021 Add N copies of inferior ID.  The new inferior has the same\n\
1022 executable loaded as the copied inferior.  If -copies is not specified,\n\
1023 adds 1 copy.  If ID is not specified, it is the current inferior\n\
1024 that is cloned."));
1025
1026   add_cmd ("inferiors", class_run, detach_inferior_command, _("\
1027 Detach from inferior ID (or list of IDS)."),
1028            &detachlist);
1029
1030   add_cmd ("inferiors", class_run, kill_inferior_command, _("\
1031 Kill inferior ID (or list of IDs)."),
1032            &killlist);
1033
1034   add_cmd ("inferior", class_run, inferior_command, _("\
1035 Use this command to switch between inferiors.\n\
1036 The new inferior ID must be currently known."),
1037            &cmdlist);
1038
1039   add_setshow_boolean_cmd ("inferior-events", no_class,
1040          &print_inferior_events, _("\
1041 Set printing of inferior events (e.g., inferior start and exit)."), _("\
1042 Show printing of inferior events (e.g., inferior start and exit)."), NULL,
1043          NULL,
1044          show_print_inferior_events,
1045          &setprintlist, &showprintlist);
1046
1047   create_internalvar_type_lazy ("_inferior", &inferior_funcs, NULL);
1048 }